1. Field of the Invention
The present invention relates to an active light ray sensitive or radioactive ray sensitive resin composition, and an active light ray sensitive or radioactive ray sensitive film and a pattern-forming method using the same. For example, the present invention relates to an active light ray sensitive or radioactive ray sensitive resin composition which is preferably used in super-micro-lithography processes such as the manufacture of a super LSI and a high-capacity microchip, and other photo-fabrication processes, and an active light ray sensitive or radioactive ray sensitive film and a pattern-forming method using the same.
2. Description of the Related Art
In a process for manufacturing semiconductor devices such as an IC, LSI, and the like, fine processing using lithography with a photoresist composition has been conventionally carried out. In recent years, ultrafine pattern configuration of a sub-micron region and a quarter micron region has been required in accordance with higher integration of integrated circuits. In such a circumstance, an exposure wavelength has also showed a tendency to become shorter such as from g rays to i rays, and further to KrF excimer laser rays. Further, besides KrF excimer laser rays, development of lithography using soft X-rays such as an electron beam, X-rays, EUV light, or the like has also been progressing recently.
In particular, electron beam lithography is positioned as a pattern-forming technique of the next generation or the next after the next generation, and a positive resist of high sensitivity and high resolution is desired. For shortening the processing time of wafers, increase of sensitivity is a particularly important problem. However, pursuit of higher sensitivity in a positive resist for electron beams is accompanied by not only lowering of resolving power but also deterioration of line edge roughness; accordingly development of a resist satisfying these characteristics at the same time is strongly desired. Here, line edge roughness means that, since the edge at the interface between the pattern of a resist and a substrate irregularly fluctuates in the perpendicular direction to the line direction due to the characteristics of the resist, an uneven edge is seen when the pattern is viewed just above. This unevenness is transferred to the substrate in the etching process of using the resist as a mask and deteriorates electric characteristics to lower the yield. In particular, in a super fine region of 0.25 μm or less, line edge roughness is an extremely important problem to be improved. High sensitivity, high resolution, good pattern configuration, and good line edge roughness are in a tradeoff relationship, and how to satisfy these characteristics at the same time is very important.
It is also an important problem to satisfy high sensitivity, high resolution, good pattern configuration, and good line edge roughness at the same time in lithography using X-rays or EUV light, and a solution thereof is required.
Furthermore, in the case of using a light source emitting EUV light, the wavelength of the light belonging to an extreme-ultraviolet region and the energy of the light is high. Therefore, unlike a conventional light source, the light source emitting EUV light bring about such a prominent outgassing problem that a compound in an active light ray sensitive or radioactive ray sensitive film is destroyed by fragmentation and volatizes as a low-molecular-weight component during exposure to contaminate the environment in the exposure device.
As a method for solving these problems, use of a resin having a photoacid generator in the polymer main chain or side chain is investigated (see JP1997-325497A (JPH09-325497A), JP1998-221852A (JPH10-221852A), JP2006-178317A, JP2007-197718A, WO06/121096A, and US2006/121390A).
However, in JP1997-325497A (JPH09-325497A), a mixed system including a resin having a photoacid generator and a dissolution inhibiting compound whose solubility in an alkali developing liquid is increased by acid decomposition is used, so that because of the heterogeneous mixing of these materials, it is difficult to realize desirable pattern configuration and line edge roughness.
Furthermore, JP1998-221852A (JPH10-221852A), JP2006-178317A, JP2007-197718A, WO06/121096A, and US2006/121390A disclose a resin containing in the same molecule both a photoacid generating group and a group whose solubility in an alkali developing liquid is increased by acid decomposition, but it does not seem quite proper to state that the sensitivity to electron beams, X-rays, or EUV light is satisfactory.
As for the techniques as described in JP1997-325497A (JPH09-325497A), JP1998-221852A (JPH10-221852A), JP2006-178317A, JP2007-197718A, WO06/121096A, and US2006/121390A, if an acid generating site corresponding to an acid generator is included in a resin, there is a tendency that miscibility of the acid generator with the resin is insufficient, or for example, an acid generated from the acid generator due to exposure expands to an unintended region (unexposed portion and the like), which leads to reduction in deterioration of resolution. In addition, since a low-molecular-weight acid generator is not present, for example, in the case of irradiation with EUV light, there is a tendency that outgassing generation derived from the low-molecular-weight component is further reduced. However, this technique also has a task particularly to further improve the sensitivity to an electron beam, X-rays, or EUV light.
Particularly, it is the present situation in which in addition to further improvement of resolution or outgassing characteristics, better performances in sensitivity, line edge roughness, and pattern configuration are also demanded at the same time, in electron beam, X-rays, or EUV light lithography.
Fine processing with a resist composition is not only directly used in the manufacture of integrated circuits but also is applied to the manufacture of a mold structure for what is called imprinting (see, for example, JP2004-158287A, JP2008-162101A, and “Fundamentals of nanoimprint and its technology development/application deployment-technology of nanoimprint substrate and its latest technology deployment” edited by Yoshihiko Hirai, published by Frontier Publishing (issued in June, 2006)). Therefore, even when X-rays, soft X-rays, or an electron beam is used as an exposure light source, it is an important problem to satisfy high sensitivity, high resolution, good pattern configuration, and good roughness characteristics at the same time, and a solution thereof is required.